Concepts and Experiences for Higher Plant Efficiency With Modern Advanced Boiler and Incineration Technology

2010 ◽  
Author(s):  
Armin Main ◽  
Thomas Maghon
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Fossil Fuels ◽  
Live Steam ◽  
Gas Temperature ◽  
Higher Plant ◽  
Advantages And Disadvantages ◽  
Boiler Tubes ◽  
Steam Parameters ◽  
Plant Efficiency

The efforts for reducing CO2 Emissions into atmosphere and increasing costs for fossil fuels concepts are the drivers for Energy from Waste (EfW) facilities with higher plant efficiency. In the past steam parameters for EfW were requested mainly at 40 bars and 400 °C (580 psi and 752 F). In case of coal fired power plants at the same location as the EfW facilities higher steam parameters at 90 bar, 520 °C (1305 psi, 968 F) have been used for the design of stoker and boiler. This long-term experience with higher steam parameters is the platform for the todays and future demand in higher plant efficiency. Increase in EfW plant efficiency is achievable by increasing temperature and pressure of live steam going along with optimized combustion conditions when using well proven grate technology for waste incineration. On the other hand higher steam parameters result in higher corrosion rates on the boiler tubes and the optimization of the combustion conditions are limited by the burn out quality requirements of slag and flue gas. Advantages and disadvantages have therefore to be balanced carefully. This paper will present different measures for optimized boiler and combustion conditions compared to an EfW plant with live steam at 40 bars and 400 °C (580 psi and 752 F) and 60% excess of combustion air. Plants operated at these conditions have very low maintenance costs created by corrosion of boiler tubes and show performance with very high availability. The following parameters and experiences will be evaluated: - reduction of excess air; - flue gas temperature at boiler outlet; - higher steam parameters (pressure and temperature); - heating surfaces for steam superheating in the radiation boiler section; - steam reheating; - external superheaters using auxiliary fuels. The comparison of the different methods for increasing the efficiency together with resulting technology challenges incorporates the experiences from modern EfW reference facilities built in Naples/Italy, Ruedersdorf (Berlin)/Germany and Heringen/Germany.

Study on Oil-Ash Corrosion and Coal-Ash Corrosion Occurred in the Flue-Gas Side of Fossil Power Plant

2011 ◽  
Vol 418-420 ◽  
pp. 918-921
Author(s):  
Yong Yan Zhou ◽  
Yu Zhou ◽  
Guo Hua Lu ◽  
Tian Sheng Chen
Keyword(s):  
Flue Gas ◽  
High Speed ◽  
Fossil Fuels ◽  
Influence Factors ◽  
Heating Surface ◽  
Coal Ash ◽  
Chemical Corrosion ◽  
Boiler Tubes ◽  
Prevention Methods ◽  
Fossil Power Plant

A large number of high-speed soot particles would be produced after fossil fuels' (oil or coal) combustion in the boiler. These high-speed particles not only directly attack the heating surface of boiler tubes (damaging the tubes mechanically), but also condensate on the wall, causing even more serious chemical corrosion. The discussion has deeply studied the occurrence sites, reaction mechanism, influence factors as well as identification and prevention methods of oil-ash corrosion, coal-ash corrosion, so it would have a positive guiding significance for reducing (or preventing) the flue-gas side corrosion.

Gas Turbines for Coal-Fired Turbocharged PFBC Boiler Power Plants

1984 ◽  
Author(s):  
Richard Wenglarz ◽  
Steven Drenker
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Power Plants ◽  
Modular Construction ◽  
Fluidized Bed Combustion ◽  
Gas Temperature ◽  
Utility Industry ◽  
Advantages And Disadvantages ◽  
Construction Methods ◽  
Standard Gas

A coal-fired turbocharged boiler using fluidized bed combustion at high pressure would be more compact than a pulverized coal fired boiler. The smaller boiler size could permit the utility industry to adopt efficient modular construction methods now widely used in other industries. A commercial turbocharger of the capacity needed to run a 250 MWe power plant doe not exist; commercial gas turbines of the correct capacity exist, but they are not matched to this cycle’s gas temperature of less than 538°C (1000°F). In order to avoid impeding the development of the technology, it will probably be desirable to use existing machines to the maximum extent possible. This paper explores the advantages and disadvantages of applying either standard gas turbines or modified standard gas turbines to the turbocharged boiler.

scholarly journals Improving the efficiency of power boilers by cooling the flue gases to the lowest possible temperature under the conditions of safe operation of reinforced concrete and brick chimneys of power plants

2018 ◽  
Vol 245 ◽  
pp. 07014 ◽  
Author(s):  
Evgeny Ibragimov ◽  
Sergei Cherkasov
Keyword(s):  
Reinforced Concrete ◽  
Power Plant ◽  
Flue Gas ◽  
Power Plants ◽  
Thermal Power ◽  
Operating Mode ◽  
Flue Gases ◽  
Technical Solution ◽  
Gas Temperature ◽  
Safe Operation

The article presents data on the calculated values of improving the efficiency of fuel use at the thermal power plant as a result of the introduction of a technical solution for cooling the flue gases of boilers to the lowest possible temperature under the conditions of safe operation of reinforced concrete and brick chimneys with a constant value of the flue gas temperature, when changing the operating mode of the boiler.

scholarly journals Performance improvement of a 330MWe power plant by flue gas heat recovery system

2016 ◽  
Vol 20 (1) ◽  
pp. 303-314
Author(s):  
Changchun Xu ◽  
Min Xu ◽  
Ming Zhao ◽  
Junyu Liang ◽  
Juncong Sai ◽  
...  
Keyword(s):  
High Pressure ◽  
Power Plant ◽  
Flue Gas ◽  
Power Output ◽  
Heat Recovery ◽  
Waste Heat ◽  
Gas Temperature ◽  
Recovery System ◽  
Heat Recovery System ◽  
Plant Efficiency

In a utility boiler, the most heat loss is from the exhaust flue gas. In order to reduce the exhaust flue gas temperature and further boost the plant efficiency, an improved indirect flue gas heat recovery system and an additional economizer system are proposed. The waste heat of flue gas is used for high-pressure condensate regeneration heating. This reduces high pressure steam extraction from steam turbine and more power is generated. The waste heat recovery of flue gas decreases coal consumption. Other approaches for heat recovery of flue gas, direct utilization of flue gas energy and indirect flue gas heat recovery system, are also considered in this work. The proposed systems coupled with a reference 330MWe power plant are simulated using equivalent enthalpy drop method. The results show that the additional economizer scheme has the best performance. When the exhaust flue gas temperature decreases from 153? to 123?, power output increases by 6.37MWe and increment in plant efficiency is about 1.89%. For the improved indirect flue gas heat recovery system, power output increases by 5.68MWe and the increment in plant efficiency is 1.69%.

scholarly journals CFD ANALYSIS OF ECONOMIZER IN A TENGENTIAL FIRED BOILER

2013 ◽  
pp. 143-147
Author(s):  
KRUNAL P. MUDAFALE ◽  
HEMANT S. FARKADE
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Large Scale ◽  
Thermal Power ◽  
Three Dimensional ◽  
Geometrical Model ◽  
Gas Temperature ◽  
Three Dimensional Model ◽  
The Individual ◽  
Side Flow

This paper presents a simulation of the economizer zone, which allows for the condition of the shell-side flow and tube-side and tube-wall, thermal fields, and of the shell-tube heat-exchange. Selection of the economizer zone from the thermal power plant only because, it is found trends of failure that the economizer is the zone where the leakages are found more. The maximum number of cause of failure in economizer unit is due to flue gas erosion. The past failure details revels that erosion is more in U-bend areas of Economizer Unit because of increase in flue gas velocity near these bends. But it is observed that the velocity of flue gases surprisingly increases near the lower bends as compared to upper ones. The model is solved using conventional CFD techniques by STAR- CCM+ software. In which the individual tubes are treated as sub-grid features. A geometrical model is used to describe the multiplicity of heat-exchanging structures and the interconnections among them. The Computational Fluid Dynamics (CFD) approach is utilised for the creation of a three-dimensional model of the economizer coil. With equilibrium assumption applied for description of the system chemistry. The flue gas temperature, pressure and velocity field of fluid flow within an economizer tube using the actual boundary conditions have been analyzed using CFD tool. Such as the ability to quickly analyse a variety of design options without modifying the object and the availability of significantly more data to interpret the results. This study is a classic example of numerical investigation into the problem of turbulent reacting flows in large scale furnaces employed in thermal power plants for the remediation of ash deposition problems. And the experimental setup is from Chandrapur Super Thermal Power Station, Chandrapur having the unit no IV of 210 MW energy generations.

scholarly journals Exergy efficiency analysis of lignite-fired steam generator

2018 ◽  
Vol 22 (5) ◽  
pp. 2087-2101
Author(s):  
Drenusha Krasniqi-Alidema ◽  
Risto Filkoski ◽  
Marigona Krasniqi
Keyword(s):  
Steam Generator ◽  
Flue Gas ◽  
Power Plants ◽  
Thermal Power ◽  
Calorific Value ◽  
Feed Water ◽  
Low Grade ◽  
Gas Temperature ◽  
Steam Generators ◽  
Energy And Exergy

The operation of steam generators and thermal power plants is commonly evaluated on a basis of energy analysis. However, the real useful energy loss cannot be completely justified only by the First law of thermodynamics, since it does not differentiate between the quality and amount of energy. The present work aims to give a contribution towards identification of the sources and magnitude of thermodynamic inefficiencies in utility steam generators. The work deals with a parallel analysis of the energy and exergy balances of a coal-fired steam generator that belongs to a 315 MWe power generation unit. The steam generator is de-signed for operation on low grade coal - lignite with net calorific value 6280 to 9211 kJ/kg, in a cycle at 545?C/177.4 bar, with feed water temperature 251?C, combustion air preheated to 272?C and outlet flue gas temperature 160?C. Since the largest exergy dissipation in the thermal power plant cycle occurs in the steam generator, energy, and exergy balances of the furnace and heat exchanging surfaces are established in order to identify the main sources of inefficiency. On a basis of the analysis, optimization of the combustion and heat transfer processes can be achieved through a set of measures, including retrofitting option of lignite pre-drying with flue gas and air preheating with dryer exhaust gases.

scholarly journals Experimental Study on a Flue Gas Waste Heat Cascade Recovery System under Variable Working Conditions

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 324
Author(s):  
Jiayou Liu ◽  
Xiaoyun Gong ◽  
Wenhua Zhang ◽  
Fengzhong Sun ◽  
Qingbiao Wang
Keyword(s):  
Working Conditions ◽  
Air Temperature ◽  
Flue Gas ◽  
Power Plants ◽  
Waste Heat ◽  
Inlet Temperature ◽  
Performance Parameters ◽  
Gas Temperature ◽  
Recovery System ◽  
Gas Ratio

Recovering flue gas waste heat is beneficial to improving the unit efficiency in power plants. To obtain the change rules of performance parameters of a flue gas waste heat cascade recovery system (FWCRS) under variable working conditions, an experiment bench was designed and built. The variation laws of the inlet temperature and exhaust flue gas temperature of a low temperature economizer (LTE), the inlet and outlet air temperature of an air preheater (AP), the heat exchange quantities of the AP, LTE, and front-located air heater and an additional economizer (AE), as well as the waste heat recovery efficiency, the system exergy efficiency, and the energy grade replacement coefficient were obtained as the flue gas flow, flue gas temperature, bypass flue gas ratio, air temperature, and circulating water flow in AE changed. Using an orthogonal test, the flue gas temperature, bypass flue gas ratio and air temperature were proved to be the significant factors affecting the performance parameters of FWCRS, and the bypass flue gas ratio was suggested as an adjusting parameter of FWCRS under variable working conditions.

Failure of Boilers and Related Equipment

2021 ◽  
pp. 662-694
Author(s):  
Paresh Haribhakti ◽  
P.B. Joshi
Keyword(s):  
Power Plants ◽  
Fossil Fuels ◽  
General Procedure ◽  
Rankine Cycle ◽  
Damage Mechanism ◽  
Working Fluid ◽  
Representative Case ◽  
Failure Investigation ◽  
Boiler Tubes ◽  
Cycle Systems

Abstract Failures in boilers and other equipment taking place in power plants that use steam as the working fluid are discussed in this article. The discussion is mainly concerned with failures in Rankine cycle systems that use fossil fuels as the primary heat source. The general procedure and techniques followed in failure investigation of boilers and related equipment are discussed. The article is framed with an objective to provide systematic information on various damage mechanisms leading to the failure of boiler tubes, headers, and drums, supplemented by representative case studies for a greater understanding of the respective damage mechanism.

Simulation and Validation of a Mass Burn WTE Boiler Using CFD Modeling

2004 ◽  
Author(s):  
Greg Epelbaum
Keyword(s):  
Flue Gas ◽  
Cfd Modeling ◽  
Design Parameters ◽  
Air Distribution ◽  
Gas Temperature ◽  
Corrosion Rates ◽  
Velocity Surface ◽  
Boiler Tubes ◽  
Chloride Salts ◽  
Simulation And Validation

American Ref-Fuel Company (ARC) spends millions of dollars each year on corrosion related costs in the boilers. The corrosion is caused by chloride salts in the slag that deposit on the boiler tubes, coupled with the high temperatures of flue gas going through the boiler. Corrosion rates are known to be very sensitive to the flue gas temperature and velocity, surface temperature and heat flux through the slag, oxygen in flue gas distribution, etc. These parameters are primarily determined by the firing rate of the boiler, and they are also affected by combustion control and air distribution in the boiler. Some design parameters, such as surface area of refractory, tile, and inconel overlay, also affect the flue gas temperature throughout the boiler, and thereby impact corrosion.

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